Thursday, January 7, 2010

Plant Care Profile: Eastern Prickly Pear Cactus (Opuntia humifusa)

I decided to try out something new, hoping that it might be useful, so starting with this post I will try to build up a collection of plant profiles with information on the cultivation and possible uses of particular plant species. Only plants that I have personally grown with some success will be included, and I will base care instructions mostly on my own experiences with the plant. To begin with I will probably focus on unusual or exotic garden plants that I think deserve to be grown more frequently but I might branch out to include other categories of plants later on. In any case, the first plant to be featured shall be Opuntia humifusa, a very hardy species of prickly pear cactus.
Origin: As its English name suggests, Opuntia humifusa is native to much of the Eastern United States, though it appears to be relatively rare throughout much of its native range. Being a cactus, it prefers sunny, dry locations with sandy or rocky soil. Some wild specimens may be found, for example, in Point Pelee National Park in southern Ontario, which consists of a narrow sandy peninsula that juts out into Lake Erie.
USDA Hardiness Zone: Zone 4b according to various sources, at least Zone 6a based on my own experience.
Opuntia humifusa flowering in my old garden at my parents' previous home in southeastern Michigan
Size: Due to its creeping habit Opuntia humifusa will hardly exceed 8" (ca. 20cm) in height, but its horizontal spread appears to be virtually unlimited if the plant is happy. The flowers are up to 2" (ca. 5cm) across.
Flowering Time: The sulfur yellow flowers appear in late spring or early summer, depending on the local climate. Plants tend to flower more heavily the older and larger the get and since not all flowers open at the same time a plant that is a few years old may flower for several weeks.
Light Requirements: Opuntia humifusa needs full sunlight, the more the better.
Soil Requirements: Being a succulent adapted to arid conditions, Opuntia humifusa needs well-drained sandy soil. I have been most successful with this plant in a south-facing bed backed by three large specimens of Colorado blue spruce (Picea pungens). Due to the trees, the soil in the bed is mixed with a very large amount of spruce needles in various stages of decomposition which keep it light, well-aerated and well-drained. The needles also act as a light mulch, and I think the relatively dry conditions commonly found close to large spruce, fir, and pine trees also help the cactus flourish.
My first specimen of Opuntia humifusa approximately three years after it had been planted as a small cutting with two segments
Siting in the Garden: Opuntia humifusa needs a warm, sunny spot with well-drained soil. South-facing beds and borders are generally the best site for this plant, and sites protected from excessive rain, such as at the base of a south-facing wall or hedge, are ideal. Due to its low height and spreading habit Opuntia humifusa is very well suited for the front of borders, though due its tiny but very irritating spines it should be planted where it is not likely to be in the way of bare feet, shins, or hands.
Once established, Opuntia humifusa flowers abundantly for several weeks in early summer
Care: Once planted Opuntia humifusa needs very little care. Keep weeds in check around the plant is somewhat important since fast-growing weeds such as grasses can easily overtake the low-lying cactus, especially when it is young. As plants get bigger this becomes less of a problem since their ground-hugging, dense habit tends to suppress weeds. Fertilizing is generally not necessary but the plant benefits from a light cover of spruce or fir boughs during the winter months, especially if hungry wildlife is likely to frequent the garden. Do not be alarmed by the droopy, shrivelled, wrinkled look of the plants from the first frost onward. As long as conditions are not excessively wet, the plant will quickly perk up again in mid-spring, and soon afterwords a new flush of "ears" as well as flower buds begin to form.
Propagation: The easiest way to propagate Opuntia humifusa, as with most prickly pear cacti, is to separate individual segments or "ears" from the plant which are then planted. They should be set deep enough that about a third of the segment is below ground. If these cuttings are taken in the spring or early summer, they may be planted right in the spot where they are supposed to grow. They usually root quickly and will often start sprouting new segments during the same season. Some segments also often fall off during winter or early spring and these may very well be used to propagate extra plants. Opuntia humifusa may also be grown from seed; older specimens often produce quite a large number of small red "prickly pears" which ripen in late summer.
Divisions of my original specimen of Opuntia humifusa in the front yard of my parents' new home in the Detroit suburbs, flowering shortly after being transplanted
Use in the Garden: Opuntia humifusa makes a beautiful, eye-catching ground cover for dry, sunny spots, particularly at the front of beds and borders, in rock gardens, and in planting schemes emphasizing native species. With its low, spreading shape it makes a great choice as informal edging for a sunny border.

16 comments:

  1. Great post. Few people know that the northeast has its own native cactus, which should be used more often. I've noticed a few residential gardens here in Toronto using it to effect. And in Stratford, Ontario, last summer in mid-July, I was delighted to see a whole bed of opuntia fully in bloom. They were planted, as you suggest, in a bed by a south-facing wall in a courtyard.

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  2. Thanks! I hope it gives some people ideas... :)

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  3. Hi,
    My opuntia is wrinkled and has been all winter. I have hardly watered it and yet it is droopy and sad looking. The small pads have fallen off too. Is this normal and should I leave it alone to perk up when the sun comes back? (Victoria, BC)
    Thanks to anyone who can help

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    1. Hi!

      Provided that it is an Opuntia species that can take the cold, it should perk up again in spring. The wrinkling and drooping is normal; it appears to be part of the plant's survival mechanism. That some pads fall off is quite normal as well, although quite annoying when the plant is still small. The fallen pads actually make excellent propagation material; I have gotten a lot of my extra Opuntia humifusa plants - my dad complains that they are everywhere in the garden now - by picking up the fallen pads in spring and potting them up as cuttings, or even just sticking them in the ground where I wanted them to grow.

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  4. I have a Opuntia ammophila it is very similar to wat you have however mine are 5 feet tall and are getting tough to bring inside for the winter.. do you think they could survive winter weather here in Vancouver bc.

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    1. Not sure... Opuntia ammophila seems to be very closely related to Opuntia humifusa, but according to this website http://davesgarden.com/guides/pf/go/72373/ it is only hardy to Zone 10, which would mean that it basically cannot withstand any real frost.

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  5. Love this! Someone just gave me a heap of Prickly Pear. I'll plant it along the sunny edge of my fence where there are lots of rocks and sand.

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    1. That sounds excellent! The one problem I have ever had with these is that at times when I had patches in places where neighboring perennials grew too lushly they sort of overran the prickly pears so that they were no longer properly visible and their prickles became a pain when cleaning out the bed at the end of the season. Much better then to have them in a sandy, rocky place that is out of the way of other plants but nice and visible!

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  6. Thanks, I am a student on the western side of Michigan. We are thinking of planting this cactus for volunteer work to recreate the old Michigan. We thank you for how this website has helped us. We are almost ready to plant! Thanks again.

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  7. Thank you for this post. I obtained 6 specimens at the Rhode Island Native Plant Society spring sale, and have planted them in various spots in my rock garden located on a south facing puddingstone outcropping right next to the coast. I will keep you posted on their success. Other native succulents have done very well for me.

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    1. That sounds like it should be great! Just the other day I saw a huge patch flowering on a rocky slope on the edge of the highway here in the Boston suburbs, which should make for similar growing conditions.

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  8. I have the same cactus but it's droopy and wrinkled now during the summer. It's very hot here in North Carolina so I can't understand why. Does it need more water or less?

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    1. Has it been very dry? It does take a fair bit of water during the summer, but not usually so much as to need extra watering.

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  9. I just move into my new home and out front is a sprawling Opuntia humifusa. I would like to cut it back and transplant it in a new location. Any suggestions or guidelines?

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    1. Opuntia humifusa is quite hardy and takes transplanting well - just make sure you plant it a bit raised, so that as the soil settles it does not end up sitting in a depression where at best it catches a lot of dry leaves and other debris and at worst will suffer from too much moisture. Alternately, you can cut of pieces ("ears") and plant them as cuttings where you want them to grow by inserting the bottom third or half of them in the ground. It is also a good idea to wear gloves while handling them, because the tiny spines come off the plant almost immediately but are very hard to remove from the skin.

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  10. I love the Opuntia humifusa cacti.They are one of my favorite cacti because they are from Massachusetts where I am from.I have been growing them for years and have seen them in many places in the wild.They are a very variable species in the way they look in different parts of its native range.In Massachusetts,for example,the northern limit of its range they are completely spineless which is unusual for the Opuntia humifusa(except glochids)and they have yellow flowers,As you head out of New England the Opuntia humifusas have more spines on the pads the futher west and south you go out of New England and the more common the plants get.They also tend to have more orange color in the center of the yellow flowers,as opposed to just yellow flowers.They also hybridize with other opuntia species where the natural ranges overlap.They are very common to see in the wild if you know where to look like in many southern appalachians mountains that are rocky where they grow in the full sun(like stone mountain Georgia) where they found all over place and also along the atlantic coast of the usa where they are common from Forida up to southern New Jersey pine barrons.I've seen lots of them on the outer Cape cod as well where they are very rare.From what I know,they grow from Chatham north to Truro and on Nantucket in Massachusetts unless there is more I don't know about.There are some huge patches of Opuntia Humifusa like at the Mass Audubon's Wellfleet bay wildlife sanctuary in Wellfleet Massachusetts. If you ever go there,go on the Goose pond trail and there is a patch of many hundreds of pads growing behind an old abandoned beach house that is right along the trail next to the bay.They
    Were probably growing here for decades.
















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